Electric brake.



B.. R. DUNLOP.

ELECTRIC BRAKE.

APPLICATION FILED 11111.17, 1905.

1,09 1,738. Patented 11111.31, 1914.

UNITED sTATEs .PATENT OEETOE.

'ROBERT E. DUNLOP, OE COLUMBUS, OHIO, ASSIGNOE, .-EY `ivrEsNE ASSIGNMENTS, 'To THE JEFFREY 4MANUFAc'rUErNor COMPANY, :A ooEPOEATrON OE 10H10.

ELECTEICPEAK'E.

Speeication of Letters Patent.

Patented Maffei, .1914.

To aZZ whom it may concern:

Be it known that I, ROBERT It. DUNLOP, a citizen of the United States,residing at CO- lumbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Electric Brakes, of which the following is a specification, reference being had therein to the acco-mpanymg drawing. i

This invention relates to improvements in electro-magnetically operated brakes for conveyer or elevator systems adapted to prevent t-he too rapid descent of an elevator or conveyor under the action of gravlty.

Figure 1 is a planV view of the upper part of said system. Fig. 2 is a diagrammatic view showing the electro-magnetic brake, the motor, and the electrical circuit. Fig. 3ds a plan view of the Contact lever of the starting box. Fig. 4 is a longitudinal sectional view thereof. Fig. 5 is a detail view of the-over`- load circuit-breaker 35. 'd

1 represents a tipple adapted to deliver material to an elongated endless carrier or conveyor 2, which is inclined to the horizontal and is adapted to retard the'descent under gravity of the material received.

3' is a trough in which the said conveyer f operates.

'LL represents a shuntwound motor having an armature 5, the .brushes 6 and 7 and` the shunt motor field S. The armature has secured to it a pinion 9v which meshes with a gear 10 secured to the head or driving shaft 11 at the upper end of the conveyer.

' .12 is a friction brake associated with the motor shaft. type. prising the casing 18 which isrigidly secured in position,.the friction disks`14, arranged on the motor shaft and secured so as to revolve therewith but adapted 'to slide longitudinally thereon, the friction disks 15 arranged between the disks 14 and splined to the casing 13 so as to be -free to lmove lon- I {itudinally of the motor shaft but held from rotation therewith, the follower 16, the plate or head 17, and the springs- 18 arranged between said ollower and said plate and adapted to normally hold the friction disks in engagement with each other so as to pre-` vent the rotation of the motor shaft.

12 1sA an electro-magnet having the core ll2al fitted on to the motor shaft and havlng .movable element thereof. -electromagnetically operated it having a tu- It may be of any well known.v In the drawings I have shown it com-V one'ot1 its ends secured vto the follower 16. 12b 1s the energizing coil of the said electro magnet. This electro-magnet 12 is designed for sufficient strength to draw the 'follower 16-aga1nst the action of the springs 18 so as to leave the elements of the clutch 12 free to rotate relative to each other. `19 is another friction brake likewise arranged upon the motor shaft, and adapted to control the rotation thereoflf 2O indicates the stationary element of this brake and 21 the The latter is bular extension 21 which serves as the core of .the felectro magnet-22, the coil 22 of which is arranged within the stationary element 20 of the brake. A suitable spring .19a maybe interposed between the end of core 21 and the brake element 20, said spring tending normally to press the movable element `21 awayfrom the stationary element. This electro-magnet is designed for sufficient strength to draw the movable element 21o'f vthe brake 19 int-o engagement withthe sta-V tionary one 20 thereof. Tlie brake 19 is `not thrown into operation until the speed of rotation cf the motor exceeds a certain predetermined rate and as soon as it does exceedthis rate,'the electro-magnet 22 is su-iiciently energized by the current from the motor operating as a generator to cause the engage#4 ment of thebrake elements in such manner as to limit the speed of the motor shaft.

24 indicates a source of electrical supply, 24 and .24a the positive and negative conductors, respectively, therefrom. 25 is a lsingle-throw, double-pole switch'wi'th terminals 25 and 25a connected to said conductors 24 and 21a respectively. '26 is a starting box 'having the Operating lever 26. 27 is a conductor leading from said lever to the brush 6 of the`motor.

28 is a conductor leading from the terminal of the resistance in the starting box to theapole 25b of the switch.

28 is a conductor leading from the brush 7 to the pole 25 of the said switch.

The field 8 of the motor has itstermi'nals connected to the conductors 27 and 28" respectivel'v.-

29 indicates a series of resistance-contro1-- ling contacts on the starting box with which the lever 26 is adapted to engage. :'30is a contact on said box having its'end `31 'ex 55 said generator.

60 the brake 12 out of operation.

tending so that contact 31 on the lever 26 will engage with it prior to its engagement with the iirst contact of the series 29. This contact 31 is insulated from the said lever.

5 32 is a conductor connecting the said segment 30 with the conductor 28.

33 is a conductor connecting the Contact 31 on the lever'26 with one terminal of the energizing coil 12b of the electro-magnet 12. 33 is a conductor connecting the other terminal of said coil with one terminal of the energizing coil 22 of the electro-magnet 22, and 34 is a conductor connecting the other terminal of said, coil with the conduc- 15 tor 28 so tha-t this coil is connected directly f across the line when the motor is in operation either as a motoror as a genera-tor.

35 is an overload circuit-breaker arranged in the line of the conductor 34, and 36 is ar adjustable shunt arranged across the terminals of the electro-magnet 22.

It will be seen that when the conve er 2 is stationary and no current tlowin t rough the energizing coils 12b and 22 o the elec- ,tro-magnet 12 and 22, respectively, that the friction brake 12 will be set so as to prevent the rotation of the motor shaft. ln order to start the conveyer, the circuit-breaker is' closed and also the switch 25 and then the 80 current switching lever 26 of the starting box 26 is swung until Contact 31 engages the end 31 of the contact 30. Current will then pass through the energizing coils 12b and 22 of the electro-magnets l12 and 22,

35 respectively, the former, drawing the follower 16 so as to release the Jfriction between the friction disks of the brake 12 and the latter drawing the movable element 21 of the brake 19 toward the stationary element 20 thereof. This will enable the motor to 48 circuit to the motor.

Asfsoon as the momentum of the retarding conveyer reaches a certain point, in order to prevent the too rapid descent of the conveyer, the source of supply from the gen- 50 erator to the motor is cut out and the motor` operated as a generator,` the fact that it is shunt-wound insuring that its field will be excited in the same direction as it was excited when supplied with current from the The energizing coils 12 and 22 ofthe'said electro-magnets 12 and 22 being in parallel with field S will be energized by the current generated by the motor so as to operate the brake 19 and hold Should the speed of the armature shaft exceed a predetermined rate owing to the too rapid descent of the conveyer elemeiits, the" increased electro-motive force generated by ,the consequent increase of speed of rotation of the armature will cause the engagement ofthe brake elements 20 and 21, and if the frictional resistance so occasioned is not suiiicient to keep down the speed of rotation of the armature shaft, the electro-motive force generated will cause the overload circuitbreaker 35 to open, breaking the circuit to the electro-magnet and permitting the friction brake 12 to operate and stop the rotation of the motor shaft.

`While it is contemplated that the current supply will be cut off when the machine has attained a certain speed, as stated above, it should be observed that the brake mechanism will operate in lsubstantially the same manner if the current supply is not out oli'. Assuming the mechanism operating with the switch 25 closed, whenthe dynamo-electric machine attains a certain speed its electro-motive force counter to 4that of the current source will become the greater of the two and it will then supply current to energize the electro-magnets in the same manner as if the switch were open. In other wor s, the dynamo-electric machine acts'to aplly the brake 19 both when connected to the current source to run as a motor and when disconnected therefrom.

The adjustableishunt 36 may be adjusted to vary the amount of current received by the energizing coil 22 of the electro-magnet 22 and thus regulate and control the operation of the brake 19.

Many modifications of the manner of completine. the electric/al circuit an'd in the use of di erently wound motors will` suggest themselves which will contain the spirit ot' myinvention, I having herein described and shown but one of the uses to which it may be applied.

I claim- *l 1. The combination with a dynamo electric machine adapted to run either as a motor or a generator; a source of electric cnrrent supply and means, for connecting said machine with and disconnect-ing it from said source of supply, of a friction brake arranged to normally oppose the rotation of the armature shaft of the said machine, an electro-magnet having its core connected with the movable element of said brake and adapted to release` the brake from the dynamo electric machine' when operated as either a motor or a generator, a second friction brake connected to the said armature shaft of the said machine, and a second electro-magnet having its core connected with the movableelementof the last described brake `and adapted when the machine armature exceeds a predetermined speed to actuate the said brake and retard the rotation of said armature both when the machine is connected to @nd disconnected from the said source of electric current supply.

2. The combination with a dynamo electric machine adapted to run either as a motor or a generator, a source of electric current supply, means for connecting said machine With and disconnecting it from said source of current supply, of a friction brake arranged to normally oppose the rotation of the arma-ture shaft of said machine, an electro-magnet having its core connected with a movable element of said brake and adapted to release the brake when the dynamo electric machine is operated either as a motor or as a generator, a. second friction brake connected to the said armature shaft of said machine and a second electromagnet having lits core connected with the movable element of said last described brake and adapted when the machine armature eX- ceeds a predetermined speed to actuate said brake and retard the rotation of said armature both when the said machine is connected to and When it is disconnected from the said source of electric current supply,` the energizing coils of said magnetsy being connected in the circuit to the said dynamo electric machine. l

3. The combination with a dynamo electric machine adapted to run either as a-motor or as a generator, a source of electric current supply and means for connecting said machine with and disconnecting itl from the said source of electric current supl. ply, of a friction brake arranged to normally oppose the rotation of the armature shaft of said machine, an electro-magnet having its core connected With the movable element of said brake and adapted to release the brake when the dynamo electric machine is operated either as a motor or as a generator, a second friction brake connectedV to the said armature shaft of said machine, and a second electro-magnet having its core connected with the movable element of the said last described brake and adapted when the machine armature exceeds a predetermined speed to actuate the said brake and retard the `rotation of the said armature both When the said machine is connected to or disconnected from the source of elect-ric current supply, the energizing coils of the 'said'electro-magnets being connected in series with each other and in the electrical circuit to` said dynamo electric machine.

4;. The combination of a motor, 'a friction brake connected with the armature shaft of said motor and arranged to normally prevent its rotation, manually controlled power actuated means 'for releasing' said brake, a second brake connected with the armature shaft of said motor and adapted to oppose the rotation of said shaft beyond a predetermined speed, automatically operated means for actuating said second brake, and means for automatically applying the first named brake When the rotation of the mo-` tor exceeds the said predetermined speed.

5. The combinauon oi a'motor, a brake connected With the armature shaft of said motor and arranged to normally prevent its rotation, a manually controlled electromagnetic means for releasing said brake, a second brake connected with the armature shaft of said motor and adapted to oppose i lsaid motor and arranged to normally prevent lts rotation, an electro-magnetic means for releasing said brake, a second brake connected with the armature shaft of said motor and adapted to oppose the rotation of said shaft beyond a predetermined speed, electro-magnetic means for operating said second brake, and means for automatically applying the irst named brake when the ro- `tation of the armature exceeds said predeterminedspeed.

Y 7, The combination of the motor, the friction 'brake adapted normally to prevent the rotation of the armature shaft of said motor, the electro-magnet for releasing said brake, the second brake connected with the armature shaft of said motor and arranged to retard the rot-ation of the said armature shaft when it exceeds a certain predeter mined speed, and i he electro-magnet for operating the last escribed brake, the energizing coils for both of said magnets being connected directly across the currentl supply l-ine to the motor.

8. The combination .of the motor, the friction brake adapted normally to prevent. the rotation of the armature shaft of said motor, the-electro-magnet for releasing said brake, the second brake connected with the armature shaft of said motor andarranged to retard the rotation off the said armature shaft when it exceeds a certain predetermined speed, and the electro-magnet for operating the last described brake, the energizing coils ofthe sai magnets being connected in series With each other and directly across the current supply line to the motor.

9. The combination of the shunt Wound motor, the brake connected With the armature shaft of said motor andarranged normally to prevent the rotationofsaid shaft, the electro-magnet for operating thc said brake, the second brake connected With the said armature shaft/and adapted to oppose its rotation labove a. certain predetermined speed, and the electro-magnet for operating the last described brake, the energizing coils of said magnets being conne ted in parallel with the motor field.

10. The combination of the motor, the

friction bra-ke connected with the armature shaft of said motor and arranged to normally prevent its rotation, the` electromagnet for releasing, the said brake, the second friction brake connected with the said armature shaft and arranged to oppose its rotation above a predetermined speed, the electro-magnet for operating said brake, the energizing coils of the said magnets being connected in series and directly across the current supply line to the motor and the overload circuit brakerarranged 'in the circuit of the said energizing coils.

11. The combination of the motor, the friction brake connected With the armature shaft of said motor and arranged to normally prevent its'` rotation, the electro-magnet for releasing the said brake, the second friction brake connected With the said armature shaft and arranged to oppose its rotation above a predetermined speed, the electro-magnet for operating said brake, the energizing coils of the said magnets being connected in series and directly across the current supply line to the motor, the overload circuit breaker arranged in the circuit of the said energizing coils and the variable shunt in the circuit around the magnet coil of the second brake.

12. The combination of the motor,v the friction vbrake adapted to normally prevent therotation of the armature shaft of said motor, the electro-magnet for releasing said brake, the second friction brake arranged to oppose the rotation of the said armature shaft above a predetermined speed. the electro-magnet for operating the llast described brake, the energizing coils of the said electro-magnets being connected inu series with each other and also in the motor circuit, and the variable shunt interposed in the circuit aroundthe magnet coil of the second brake.

13. The combination of the motor, the source of electric current supply, the brake connected With the larmature shaft of the motor and arranged to normally prevent .rotation of said shaft, means for releasing said brake, the second brake connected With t-he armature 'shaft and adapted to oppose` its rotation above apredetermined speed, and the electro-magnet for operating the second brake, the motor and the energizing coils of saidwmagnet being connected .in parallel to thel current source. f

14. The combination of the motor, the source of electric currentsupply, the brake connected With the amature shaft of said motor and arranged normally to prevent rotation of said shaft, the electro-'magnet for operating said brake, the second brake connected With the said armature shaft-and adapted to oppose its rotation above a predetermined speed, and the electro-magnet for operating the last-named brake, the

of said brakes.

motor and the coils of said magnets being connected in parallel to the current source.

15. The combination With a dynamo-electric machine, of tWo friction brakes connected With the armature shaft of said machlne, one of said brakes being arranged to normally prevent rotation of said shaft and the other brake being arranged to oppose its rotation beyond a predetermined rate of speed, manually controlled power actuated means for releasingpthe first named brake, means for automatically applying said brake when the rotation of the armature exceeds said predetermined speed, and electro-mag-- netic means for causing the actuation of the other of said brakes. 1

16. The co1nbination vvith a dynamo-electric machine of two friction brakes connected With the armature shaft of said machine, one of said brakes being arranged to normally oppose the rotation of said shaft and the other being arranged to oppose its rotation beyond a predetermined speed, and means for simultaneously releasing one and applying the other one of said brakes.

17. The combination with a dynamo-electric machine of two friction brakes connected with the armature shaft of said machine, one of said ,brakes being arranged to normally oppose the rotation of said shaft, and the other one being arranged to oppose its rotation beyond a predetermined speed, and means for automatically and simultaneously releasing the one and applying the other one 18. The combination with a dynamo-electric machine of two friction brakes connected with the armature shaft of said machine, one of said brakes being arranged to normally oppose the rotation of said shaft and the other one being arranged to oppose its rotation beyondv a predetermined speed, and electro-magnetic devices operable simultaneously for releasing one of the brakes and for applying the other one.

19. The combination of a dynamo-electric machine, a source of electricu current supply,l tivo friction brakes connected with the armature shaft of said machine, one of said brakes being arranged to normally oppose the rotation of said shaft and the other one being arranged to oppose its rotation beyond a predetermined speed, electro-magnetic devices` electrically connected in the electrical circuit to the said machine and mechanically connected to said brakes and adapted to release thepfirst described one thereof and apply the second one, and means for connecting said electro-magnetic devices to the source of current supply prior to com:

pleting the circuit between said source and the said dynamo-electric machine.

` 20.-y The combination With a dynamo-electric machine of tWo friction brakes connected with the armature shaft of said machine,

one of said brakes bein `arranged to .normally oppose the rotatio of said shaft and .the other one being arranged to oppose its rotation beyond a predetermined speed, two

electro-magnets having their coils connected in Series and to the electrical circuit for said machine, the movable core `of one ofv said magnets being connected to the movable element of one of said brakes, and the movable core of theother of said magnets being connected to the movable element of the other one of said brakes,

and the overload circuit breaker in the elec` trical circuit for said electro-magnets.

2l. The combination with a dynamo-electric machine of two friction brakes connected with the armature shaft of said machine, one of said brakes being arranfved to normally oppose the rotation of saic shaft, and the other one being arranged to oppose its rotation beyond a predetermined speed, two electro-magnets having vtheir coils connected in series and to the electrical circuit for -said machine, the movable core of one of said magnets being connected to the movable element of one of said brakcs, and the movable core of the other of said magnets being 'connected to the movable element of the other one of said brakes, and the adjustable -shunt in the said circuit for the; magnet coils arranged to shunt the current from the coils of the second one of said magnets.

22. The combination with a dynamo-electric machinecf two friction brakes connected with thearmature shaft of said machine, one of said brakes being arranged to normally oppose the rotation of said shaft, and the other one being arranged to oppose its rotation beyond a predetermined speed, two

electro-magnets having their coils connected in series and to thel electrical circuit for said machine, the movable core of one of said magnets being connected to the movable element of one of said brakes, and the movable core of the other of said magnets being connected to the movable element of the other one of said brakes, the overload circuit breaker in the electrical circuit for said electro-magnets', and the adjustable shunt in the circuit for the magnet coils arranged to shunt the current from the coils of the second one of said magnets.

23. The combination of a motor, a source of current supply, a brake arranged to'prevent the rotation of the armature shaft of the motor above a predetermined speed, an electro-magnet for operating the said brake, the energizing coils of the said magnet being connected to the source of current supply in parallel with the motor circuit, and a variable shunt arranged to controlthe operation of the brake, substantially as set forth.

24. rlhe combination of a source of current supply, a dynamo-electric machine adapted to run either as a motor or a generator, means for connectin with and'disconnecting' 1t rom said source of supply, and an electro-magnetic brake for the armature of saidmachine having its windings connected in the 'circuit lof said machine and adapted to be energized to op-v vsaid circuit of the mach-ine for releasing said brake, means for connecting the machine to the sourcel of supply, and means connected with the lastnamed means for closing the said circuit and energizing the electro-magnetic means before the machine is connected `to the source of supply.

In testimony whereof I aiiix my signature in presence of two witnesses.

R'. R. DUNLOP.

Witnesses:

C. E. WAXBoM,

C. L. MCCONKEY.

said machine 

